// apparmor.d - Full set of apparmor profiles
// Copyright (C) 2021-2023 Alexandre Pujol <alexandre@pujol.io>
// SPDX-License-Identifier: GPL-2.0-only

package logs

import (
	"bufio"
	"fmt"
	"io"
	"regexp"
	"strings"

	"github.com/roddhjav/apparmor.d/pkg/aa"
	"github.com/roddhjav/apparmor.d/pkg/util"
	"golang.org/x/exp/slices"
)

// Colors
const (
	reset      = "\033[0m"
	fgGreen    = "\033[32m"
	fgYellow   = "\033[33m"
	fgBlue     = "\033[34m"
	fgMagenta  = "\033[35m"
	fgCian     = "\033[36m"
	fgWhite    = "\033[37m"
	boldRed    = "\033[1;31m"
	boldGreen  = "\033[1;32m"
	boldYellow = "\033[1;33m"
)

var (
	quoted                bool
	isAppArmorLogTemplate = regexp.MustCompile(`apparmor=("DENIED"|"ALLOWED"|"AUDIT")`)
	regCleanLogs          = util.ToRegexRepl([]string{
		// Clean apparmor log file
		`.*apparmor="`, `apparmor="`,
		`(peer_|)pid=[0-9]*\s`, " ",
		`\x1d`, " ",

		// Resolve classic user variables
		`/home/[^/]+/.cache`, `@{user_cache_dirs}`,
		`/home/[^/]+/.config`, `@{user_config_dirs}`,
		`/home/[^/]+/.local/share`, `@{user_share_dirs}`,
		`/home/[^/]+/.local/state`, `@{user_state_dirs}`,
		`/home/[^/]+/.local/bin`, `@{user_bin_dirs}`,
		`/home/[^/]+/.local/lib`, `@{user_lib_dirs}`,
		`/home/[^/]+/.ssh`, `@{HOME}/@{XDG_SSH_DIR}`,
		`/home/[^/]+/.gnupg`, `@{HOME}/@{XDG_GPG_DIR}`,
		`/home/[^/]+`, `@{HOME}`,

		// Resolve classic system variables
		`/usr/lib(|32|64|exec)`, `@{lib}`,
		`/usr/(|s)bin`, `@{bin}`,
		`[^/]+-linux-gnu[^/]?`, `@{multiarch}`,
		`/run/`, `@{run}/`,
		`user/[0-9]*/`, `user/@{uid}/`,
		`/proc/`, `@{PROC}/`,
		`@{PROC}/[0-9]*/`, `@{PROC}/@{pid}/`,
		`@{PROC}/@{pid}/task/[0-9]*/`, `@{PROC}/@{pid}/task/@{tid}/`,
		`/sys/`, `@{sys}/`,
		`@{PROC}@{sys}/`, `@{PROC}/sys/`,
		`pci[0-9][0-9][0-9][0-9]:[0-9][0-9]`, `@{pci_bus}`,
		`@{pci_bus}/([0-9][0-9][0-9][0-9]:[0-9][0-9]:[0-9a-f][0-9a-f]\.[0-9]/)+`, `@{pci}/`,

		// Some system glob
		`:1.[0-9]*`, `:*`, // dbus peer name
		`@{bin}/(|ba|da)sh`, `@{bin}/{,ba,da}sh`, // collect all shell
		`@{lib}/modules/[^/]+\/`, `@{lib}/modules/*/`, // strip kernel version numbers from kernel module accesses

		// Remove basic rules from abstractions/base
		`(?m)^.*/etc/[^/]+so.*$`, ``,
		`(?m)^.*@{lib}/[^/]+so.*$`, ``,
		`(?m)^.*@{lib}/locale/.*$`, ``,
		`(?m)^.*/usr/share/locale[^/]?/.*$`, ``,
		`(?m)^.*/usr/share/zoneinfo[^/]?/.*$`, ``,
		`(?m)^.*/dev/(null|zero|full|log).*$`, ``,
		`(?m)^.*/dev/(u|)random.*$`, ``,
	})
)

type AppArmorLog map[string]string

// AppArmorLogs describes all apparmor log entries
type AppArmorLogs []AppArmorLog

func splitQuoted(r rune) bool {
	if r == '"' {
		quoted = !quoted
	}
	return !quoted && r == ' '
}

func toQuote(str string) string {
	if strings.Contains(str, " ") {
		return `"` + str + `"`
	}
	return str
}

// NewApparmorLogs return a new ApparmorLogs list of map from a log file
func NewApparmorLogs(file io.Reader, profile string) AppArmorLogs {
	log := ""
	isAppArmorLog := isAppArmorLogTemplate.Copy()
	if profile != "" {
		exp := `apparmor=("DENIED"|"ALLOWED"|"AUDIT")`
		exp = fmt.Sprintf(exp+`.* (profile="%s.*"|label="%s.*")`, profile, profile)
		isAppArmorLog = regexp.MustCompile(exp)
	}

	// Select Apparmor logs
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()
		if isAppArmorLog.MatchString(line) {
			log += line + "\n"
		}
	}

	// Clean & remove doublon in logs
	for _, aa := range regCleanLogs {
		log = aa.Regex.ReplaceAllLiteralString(log, aa.Repl)
	}
	logs := strings.Split(log, "\n")
	logs = util.RemoveDuplicate(logs)

	// Parse log into ApparmorLog struct
	aaLogs := make(AppArmorLogs, 0)
	for _, log := range logs {
		quoted = false
		tmp := strings.FieldsFunc(log, splitQuoted)

		aa := make(AppArmorLog)
		for _, item := range tmp {
			kv := strings.Split(item, "=")
			if len(kv) >= 2 {
				aa[kv[0]] = strings.Trim(kv[1], `"`)
			}
		}
		aa["profile"] = util.DecodeHex(aa["profile"])
		toDecode := []string{"name", "comm"}
		for _, name := range toDecode {
			if value, ok := aa[name]; ok {
				aa[name] = util.DecodeHex(value)
			}
		}

		aaLogs = append(aaLogs, aa)
	}

	return aaLogs
}

// String returns a formatted AppArmor logs string
func (aaLogs AppArmorLogs) String() string {
	// Apparmor log states
	state := map[string]string{
		"DENIED":  boldRed + "DENIED " + reset,
		"ALLOWED": boldGreen + "ALLOWED" + reset,
		"AUDIT":   boldYellow + "AUDIT  " + reset,
	}
	// Print order of impression
	keys := []string{
		"profile", "label", // Profile name
		"operation", "name", "target",
		"mask", "bus", "path", "interface", "member", // dbus
		"info", "comm",
		"laddr", "lport", "faddr", "fport", "family", "sock_type", "protocol",
		"requested_mask", "denied_mask", "signal", "peer",
	}
	// Key to not print
	ignore := []string{
		"fsuid", "ouid", "FSUID", "OUID", "exe", "SAUID", "sauid", "terminal",
		"UID", "AUID", "hostname", "addr", "class",
	}
	// Color template to use
	colors := map[string]string{
		"profile":        fgBlue,
		"label":          fgBlue,
		"operation":      fgYellow,
		"name":           fgMagenta,
		"target":         "-> " + fgMagenta,
		"mask":           boldRed,
		"bus":            fgCian + "bus=",
		"path":           "path=" + fgWhite,
		"requested_mask": "requested_mask=" + boldRed,
		"denied_mask":    "denied_mask=" + boldRed,
		"interface":      "interface=" + fgWhite,
		"member":         "member=" + fgGreen,
	}
	res := ""
	for _, log := range aaLogs {
		seen := map[string]bool{"apparmor": true}
		res += state[log["apparmor"]]
		fsuid := log["fsuid"]
		ouid := log["ouid"]

		for _, key := range keys {
			if log[key] != "" {
				if key == "name" && fsuid == ouid && !strings.Contains(log["operation"], "dbus") {
					res += colors[key] + " owner" + reset
				}
				if colors[key] != "" {
					res += " " + colors[key] + toQuote(log[key]) + reset
				} else {
					res += " " + key + "=" + toQuote(log[key])
				}
				seen[key] = true
			}
		}

		for key, value := range log {
			if slices.Contains(ignore, key) {
				continue
			}
			if !seen[key] && value != "" {
				res += " " + key + "=" + toQuote(value)
			}
		}
		res += "\n"
	}
	return res
}

// ParseToProfiles convert the log data into a new AppArmorProfiles
func (aaLogs AppArmorLogs) ParseToProfiles() aa.AppArmorProfiles {
	profiles := make(aa.AppArmorProfiles, 0)
	for _, log := range aaLogs {
		name := ""
		if strings.Contains(log["operation"], "dbus") {
			name = log["label"]
		} else {
			name = log["profile"]
		}

		if _, ok := profiles[name]; !ok {
			profile := &aa.AppArmorProfile{}
			profile.Name = name
			profile.AddRule(log)
			profiles[name] = profile
		} else {
			profiles[name].AddRule(log)
		}
	}
	return profiles
}